Mike Chambers from Adobe just released a new iPhone app for viewing the ActionScript 3 documentation.
The app includes class references for Adobe AIR 1.5, Adobe Flex 3.2 and Flash Player 10. I've been testing it this weekend and it has run great.
There is more information on Mike's website for the app, including a download link for the iTunes App Store. If you want to install the app directly on your phone, you'll need to search for "Mike Chambers" to find the app while it works its way into the App Store search.